Method of making coiled coils



.Y Sept. 3, 1935. R. H. BEEBE METHOD OF MAKING COIIILED4 COILS Fil'ed Aug. 22. 195s I 2 sheets-sheet 1 |NvENTo f2 H. 555B ATTORNEY Y Sept. 3, 1935. R. H. `BEEBE 2,013,432

METHOD OF MAKING COILED COILs Y Filed Aug. 22, 1933 2 Sheets-Sheet 2 INVENTOR R. Il. f-'BE ATToRNE Patented xSept. 3, 1935 M'ETHOD 0F MAKING COILED COILS Raymond H. Beebe, Glen Ridge, N. J, assignor to Westinghouse Lamp Company, a corporation of 4 Pennsylvania Application August 22, 1933, Serial No. 686,205

14 Claims.

This invention relates to the method of winding a helically wound wire into a secondary helix and relates more particularly to the manufacture of what may be termed a coiled-coil filament for 5 incandescent electric lamps.

In the manufacture of incandescent electric lamps it is the practice to helically wind a wire, usually tungsten Wire, into helical form and of suicent length to provide the necessary'resistance so that the coiled lament may constitute a light, source upon the passage of electrical energy therethrough. Obviously, filaments* for lamps of diierent wattages vary in the length, pitch and diameter of the coil. l5 Although a coiled lamp filament has been found practical to give satisfactory commercial results, it has been proposedvto again coil the coiled filament to produce a light vsource having the shape of a helix, the turns of which are made of helically Wound Wire and consist of what may be termed primary and secondary coils.

It has been found that an incandescent lamp filament of the coiled-coil type consumes considerable less electric current than a straight filament or one wound in a single helix having the same absolute length and with the same current consumption, a coiled-coil filament has a higher light emission. This may be attributed to the mutual heating elect between separate sections of the turns of the filament lying close to one another. Furthermore, it has been found that when using a coiled-coil filament the relatively larger amount of light produced isconfined to a comparatively small space. 'I'his is particularly true when the coiled-coil filament operates in a bulb having a lling of an inert gas.

It has also been found that by the use of a `filament or light source as above described that the mounting of the sameV is simplified in that a 40 lesser number of support wires may be employed,

thus reducing the material cost of the device.

Although the use of the coiled-coil type of filament has been heretofore proposed, certain difficulties existed in producing this type of filament,

particularly in producing such coiled-coil la- .4; the proper length -for use in lamps and themandrel is dissolved out in a bath which attacks the mandrel but not the tungsten wire.

The other method of manufacturing helically- Wound filaments consists in driving a tungsten Wire into a cavity die so that it issues in the form 5 of a helix in the absence of a mandrel. This latter practice, which is termed mandrelless winding is more clearly shown in Patent No. 1,670,499 issued May 22, 1928.

In winding filaments on a machine of the man-r 10 l drelless type it is possible to produce coiled sections at a high rate of speed and since the operation of removing a mandrel ist eliminated, the cost of manufacturing is appreciably reduced.

By reason of the high rate ofl speed at which 15 coils may be produced on the mandrelless coil Winding machine and since no mandrel removing operation is required, it is desirable, when yconsidering the manufacture of coiled-coil filaments, to provide a method of producing such 20 filaments in connection With the mandrelless coilwinding method and the present method makes it possible to accomplish this end.

It is to be understood, however, that the present method, although shown and described herein as 25 applied to'the coiling of a coiled filament Wire wherein the original coil was made on a mandrelless machine, that the present method is applicable to coils produced on a mandrel machine after the mandrel has been removed. 30

It is an object of the present invention, therefore, to provide a simple and effective method of helically coiling a helically coiled wire.

Another object of the invention is to provide a method whereby a lamentary wire may be 35 wound to helical form, and the helix as formed, may be coiled into a second helix.

Another object of the invention is to provide means for guiding a wire into a helix of a given pitch and in changing the space relation of the 40 turns of the helix to produce a second helix.-

Other objects and advantages of the invention will be understood from the following description together with the accompanying drawings, in which Fig. 1 is a side elevational view of amachine for winding a helically coiled wire into a secondary helix and shows means for making the primary coil;

Fig. 2 is a view taken on line II-Il in Fig. l; Fig. 3 is an enlarged diagrammatic view showing the relative positions of the primary coil and the spacer member for forming the primary coil into a secondary coil;

Fig. 4 is a view taken on line IV-IV in Fig.

3, and

Fig. 5 shows a lamp stem including a coiledcoil lament.

Although the present invention may be practiced to coil a helically wound wire whether it is fed from a spool or other source of supply the invention may be utilized in connection with a `mandrelless coil winding machine such as disclosed in the above. mentioned patent.

As illustrated the present machine may include a coil winding die I0 which is part of a mandrelless coil winding machine Il. The complete' machine is clearly shown in the above mentioned patent and it is thought only necessary in the present drawing to show the force rollers I2 and I3 which drive a filament wire I4 into a die l0. The die I0 usually consists of a diamond mounted on a die rod I5. The diamond is pro-` vided with a concave cavity into which the lament wire I4 is thrust so thatit issues in the form of a helix I6. This helix may, for thepurfpose'of the present description, be considered as adjust it in a horizontal plane the foot piece 21| is provided with a threaded aperture 26 to receive a screw 21 the free end of which is provided with a head 28 which abuts againstA a plate 29 so that a rotation of the head 28 causing a rotation of the screw will serve to move.

the bracket 2|.

When the helically wound filament or primary coil I6 travels through the passage |'I it rotates about the longitudinal axis of the helix, this rotation being caused by the mandrelless operation of coiling. The filament rotates at relatively high speed since in practice it; is necessary to speed up the coiling operation to of production of other lamp parts.

For the purpose of winding the primarycoil into a secondary coil the sleeve I8 is provided with a nose piece 3| and it is at this point that meet the rate the operation of forming the secondary coil isV performed.

It has been found that if the turns of a helically wound coil of a given pitch are spread apart at predetermined-points on the circumference `of the coil thatr the helically wound coil will take the form of another helix. The present construction'shows one means of operating on a primary coll to progressively move a member or spreader between successive turns of the coil. When operating upon a. helically wound coil as it issues from a coil winding machine and is thus rotating, it is necessary to provide means so coordinated and timed as to perform the spreading operation after each revolution of the primary coil so that the point at which the spreading takes place is always the same with respect to the circumference v,of the primary coil.

It has been found practical to perform the' spreading operation by means of a knife-like member 32 which may be carried on a disc 33. 'I'he disc is rotatable on ashaft 34 driven' by a suitable source of power (not shown). The disc `33 is provided with a toothed segment 35 disposed in mesh with the pinion 22. The segment and pinion are so proportioned and arranged that a movement of the segment will cause one complete rotation of the pinion. l This will obviously cause a, complete rotation of the pinion I9 and sle'eve I8 which is rotatable therewith. Extending from the nose piece 3| of the sleeve is a guide finger or stub mandrel 36 and as the coil I6 issues from the sleeve it passes adjacent to and travels over an abutting surface 31 (see Fig. 4) on the mandrel 36. At this point a separator member or blade is moved between the turns. This blade is carried by the disc 33 and is so timed in its operation that with each complete rotation of the primary coil about its axis the l be the same as used for cutting up the mandrelless wound wire as shown in the above mentionedpatent.

The mandrel 36 is, as above described, carried on the spindle I8 and therefore rotates with thev primary coil so that the secondary coil'asit is made will move with the primary coil and be held under control and fed into the guide tube II. With the present construction the primary coil winding operation is terminated during the movement of the blade 32 between the turns. 'I'he operation of making the primary coil may. however, be made continuous by providing a plurality of blades .32 operating in timed relation to the rate of rectilinear movement of the primary coil. It will be appreciated that the operation of the blade 32 must be timed accurately and in the present construction the disc 33 is adjustable to move the segment toward or away from the pinion 22 thus changing the pitch diameter and varying the ldegree of 'movement of the pinions and consequently the mandrel 36 on the nose piece 3|. The nose piece is also slightly adjustable and is Held against relative movement by a set screwv 42 extending through a slot 43 in a flange on the sleeve I8. 'I'he sleeve and consequently the arbor is thus adjustable with respect to the Apath of movement of the blade 32 and by such adjustments the pitch of the secondary coil may be varied.

If the operation of making a secondary coil is to be performed on a helical primary coil fed from a source of supply as from a spool or if short lengths of coiled sections are to be again coiled it is obvious that the primary coil would not be rotating and it would therefore only be necessary to actuate the blades in a denite time relation to the rectilinear path of movement of the primary coil.

The blade 32 may be made of sharp knife-like form having a wedge shape. If the blade/'is so disposed that the edge of the knife just' passes between the turns which arethus spread very. slightly, a secondary coil of relatively large diameter will result. If the bladeis moved so' that small diameter will result. It will, therefore, be evident' that by controlling the action of the spreader or knife, the diameter of the secondary coil may be controlled. The coil turn separator 32 is shown with a single blade but it is to be understood that the number of blades may vary and if desirable a plurality of blades may be used and operated to enter the space between each'successive turn at the proper point about the` circumference of the cylindrical primary coil.

When producing a light source in the form of a helically wound wire for a lamp of ja given wattage certain conditions must be strictly observed. The length of the selected-diameter filament wire contained in the light source must be exact so that the predetermined resistance will be obtained and this length of wire must be contained in a given number of turns, 'the pitch of the-helix must be kept uniform and the outside diameter of the helix held constant.

The problem involved will be appreciated when it is understood that filament wire ranges from about one-half mil or less to about ve mils in diameter. This filament wire is then wound into a helix having an outsidediameter of about 40 j mils or less.

Ywhen winding a helical filament on a mandrelless machine, the wire is free from tensional stress as distinguished from the mandrel wound lament which is subjected to tensional stress during the winding operation.

When making a coiled-coil filament, therefore, it is desirable to utilize mandrelless wound filaments but it is also important to preserve the advantage gained by reason of the mandrelless Winding. When the secondary winding is accomplished as heretofore proposed by Winding the helixon a mandrel to produce the secondary coil, it is necessary to tightly Wrap the primary coil on the mandrel. This resultsin a stretching or distortion of the wire and it is usually necessary to heat and thus soften the secondary coil to set it and prevent a change in diameter when the mandrel is removed. These operations tend to change the character of the wire and to some degree nullify the advantage gained bythe mandrelless winding. y

The present method makes it possibleto produce a coiled-coil which is free from detrimental stress or strains which-may tend to cause the final iilamentto sag when used as a light source.

In the present' method the operation of separating to change the space relation between portions of adjacent turns at a given point, makes it possible to produce a secondary coil in the absence of any tensional force, thus giving a new article in the form of a. coiled-coil which possesses properties not found in other coils of similar form made by other methods.

`When mounting the usual type of lamp lament it is the practice to either clamp or weld the ends or terminals of the lament to the lead rwires andthe saine practice may be followed with the present coiled-coil. When making a coiled-coil lament it has been found desirable intermittent operation of the separator will then produce an indefinite length of filament composed of coiled-coil sections separated and connected by sections of ,the primary coil. The length of the sections of primary coil may be so proportioned that the coiled-coil portions may be separated by severing the primary coils midway between adjacent coiled-coil sections thus giving iilamentary bodies to serve as light sources with terminals which facilitate the clamping or welding operation.

It is to be understood, however, that coiledcoil filaments may be used and are practical even without such terminals since the ends of the coiled-coils may be clamped or welded to support wires. In some cases the provision of terminals of the primary coil are desirable especially when coils of large diameter are used as in high Wattage lamps.

It has been found that the present method makes it possible to produce coiled-coils of relatively large diameter. This is a decided advantage since when making coiled-coils by Winding a primary coil on a mandrel as heretofore proposed it has been found that satisfactory results any tensional stress upon the wire, it has beenl found possible to Wind coiled-coils having a wide range of diameters. A coiled-coil produced by the present method, as Well as the method employed, constitute an advance step in the art of making incandescent lamps in that not only is it possible to save time and labor, but a better product is produced.

Although a preferred embodiment of the invention is shown and described herein it is to be understood that modifications may be made therein without departing from the spirit and scope of the invention pended claims.

What is claimed is:

1. The method of 'winding a primary helix wire intov a secondary helix which comprises moving -the primary helix through a predetermined path and in individually separating adjacent turns of the primary helix-to produce a secondary helix.

2. The method of Winding a primary helix Wire into a secondary helix which comprises moving the primary helix through a predetermined path, rotating the primary coil about its longitudinal axis and in applying a force between the turns to change the space relation of portions of adjacent turns thereof to form said primary coil into a secondary coil.

3. The method of Winding a primary helix wire into a secondary helix which comprises moving the primary helix through a predetermined path, and in applying a force against the turns thereof to form said primary coil into a secondary coil.

4. The method of making coiled-coil laments which comprises supporting a helically as set forth in the ap-` the turns thereof to separate them and cause the coiled lament to form -a secondary helix.

5. The method of forming a wire helix into a secondary helix which comprises moving the lilament through a given path and intermittently applying a force between the turns of the Viirst named helix to cause them to separateV and form a second helix.

6. The method of winding a primary helically wound wire into a secondary helical coil which 1 comprisescausing a separator element to move between the turns of the primary coil.

7. The method of winding a primary helically wound wire into a secondary helical coil which comprises causing a separator element to move through a path substantially transverse to the longitudinal axis of the primary coil and successively pass between the turns thereof.

`8. 'I'he method of winding a primary helically wound wire into a secondary helical coil which comprises causing a separator element to successively'pass between the turns of the primary coil and in intermittently interruptingA the operation of the separator element.-V l

9. The method of winding a primary helically wound wire into a secondary helical coil which comprises causing a separator element to move through a path substantially transverse to the longitudinal axis of the primary coil and pass between the turns thereof and in intermittently terminating the operation of said element.

10. 'I'he method of winding a wire into a primary helix and a secondary helix which comprises winding a wire into ahelix, causing sald helix to move through a. given path and in applying a. force against the turns of the helix successively to cause the helix to take the form of a second helix.

11. 'I'he method of making a coiled-coil lament which comprises moving a lament wire into y a die to produce a helix and in applying alforce against the turns of the issuing helix to produce a. secondary helix.

l2. The method of making a coiled-coil 1a' ment which comprises moving a-.fllament wire into a die to produce ahelically wound Wire and in individually separating the turns along one side of the helix to cause the helix to take the shape of another helix. y

13. A lamp filament composed of a ilamentary wire free from tensional stress coiled to helical form by a pushing operation and again coiled to form a secondary helix by an individual separation of the turns of the first helix in the absence of tensional stress. 14. A filament for an incandescent electric lamp comprising a wire coiled to helical form by a pushing operation to avoid tensional stress in the wire and again coiled into a secondary helix by an individual separation of the turns of the first helix to maintain the absence of tensional stress.

RAYMOND H. BEEBE. 

